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Prednisolone for Veterinary Use

by Barbara Forney, VMD

Basic Information

Prednisolone is a synthetic corticosteroid with approximately four times the anti-inflammatory potency of hydrocortisone. Corticosteroids have an effect on practically every system of the body. They are important in normal protein, carbohydrate and fat metabolism, and for their role in controlling inflammation. They have both strong beneficial effects and a definite potential to cause negative side-effects.

Prednisolone commonly is used in both small- and large-animal veterinary medicine. It may be given by injection, orally, ophthalmically, or topically. Preparations for topical use may include other active ingredients such as antibiotics, antifungals, or miticides.

Prednisone is converted by the liver to prednisolone. Animals in hepatic failure should receive prednisolone instead of prednisone. Systemic prednisolone is preferred for use in cats over prednisone because there is some question if cats are able to convert prednisone to prednisolone. Prednisolone should be used in horses rather than prednisone because horses do not absorb prednisone.

Dogs and Cats

Prednisolone is used systemically in high doses in emergencies for anaphylactic reactions, spinal cord trauma, endotoxemic or septic shock. It also is used to manage and treat diseases of practically every organ system in the dog and cat including: gastrointestinal, renal, respiratory, liver, adrenal/endocrine, central nervous system, hematopoietic, dermatologic, musculoskeletal, some autoimmune diseases, some reproductive disorders, some toxicosis, and some neoplastic conditions.

Horses

Prednisolone is given systemically to decrease inflammatory and immune responses. It is used in high doses in emergencies for anaphylactic reactions, spinal-cord trauma or shock. It is used in lower doses to treat allergic reactions such as Chronic Obstructive Pulmonary Disease, hives, itching, inflammatory diseases, and to manage and treat immune-mediated hemolytic anemia and thrombocytopenia. Other corticosteroids are preferred for intra-articular use.

Prednisolone Side Effects

• Systemic side-effects to corticosteroids generally are dependent on dose and duration of treatment. Adrenocorticosteroids have effects on every body system.
• Polyuria, polydipsia, and muscle wasting can be seen with prolonged corticosteroid use.

Precautions

• Chronic or inappropriate use of corticosteroids including prednisolone can cause life-threatening hormonal and metabolic changes, specifically iatrogenic Cushing's Disease or Addison's Disease.
• Corticosteroids such as prednisolone should not be used in animals with systemic fungal infection.
• Adverse effects due to corticosteroid treatment usually occur with long-term administration of the drug, especially when high doses are used. If possible, the longer-acting corticosteroids should be avoided for long-term therapy. Prednisolone is considered a shorter-acting corticosteroid. Alternate day therapy with short-acting preparations is preferred. Animals that have received long-term therapy should be withdrawn slowly by tapering the dosage and prolonging the interval between doses.
• Corticosteroids suppress immune response. Animals receiving systemic corticosteroids may be more susceptible to bacterial or viral infections. Systemic corticosteroids can mask signs of infection, such as an elevated temperature.
• Corticosteroids can cause or worsen gastric ulcers.
• Corticosteroids should be avoided or used very carefully in young animals both because of immune suppression and the risk of GI ulcers in this population.
• Corticosteroids have been implicated as a cause of laminitis in horses and ponies. Some corticosteroids are thought to be more likely to cause laminitis than others and prednisolone historically has not been considered to be in the higher-risk category. Pony breeds and horses with pituitary pars intermedia dysfunction or metabolic syndrome may be more susceptible to developing laminitis.
• Corticosteroids should be avoided during pregnancy and lactation unless the benefits outweigh the risks. Large doses in early pregnancy may be teratogenic. Corticosteroids will cross into maternal milk.

Drug Interactions

• When amphotericin B or diuretics such as furosemide are given with corticosteroids, there is an increased risk of electrolyte imbalances due to calcium and potassium losses. If digitalis also is being used in the same animal the risk of digitalis toxicity increases with potassium depletion.
• Corticosteroid use may increase the insulin requirement because they stimulate gluconeogenesis.
• The immune response to vaccination may be reduced when corticosteroids are given at the same time. Animals on immunosuppressive doses of corticosteroids should not be given modified live virus vaccines.
• The risk of GI ulcers may be increased if corticosteroids and other drugs prone to causing ulcers such as NSAIDs are given at the same time.
• Corticosteroids should not be given intravenously with fluids containing calcium.

Overdose

Short-term administration of even large doses is unlikely to cause serious harmful systemic effects due to adrenal suppression. Problems associated with long-term administration of prednisolone relate to suppression of normal adrenal function, iatrogenic Cushing's Disease, and metabolic crisis due to abrupt withdrawal.

About the Author

Dr. Barbara Forney is a veterinary practitioner in Chester County, Pennsylvania. She has a master's degree in animal science from the University of Delaware and graduated from the University of Pennsylvania School of Veterinary Medicine in 1982.

She began to develop her interest in client education and medical writing in 1997. Recent publications include portions of The Pill Book Guide to Medication for Your Dog and Cat, and most recently Understanding Equine Medications published by the Bloodhorse.

Dr. Forney is an FEI veterinarian and an active member of the AAEP, AVMA, and AMWA.